package orbit

import (
	"context"
	"errors"
	"net/url"
	"strconv"
	"strings"
	"time"
	"unicode/utf8"
)

// ListTasks 查询同一队列内的任务摘要，筛选固定后沿NextCursor分页；不承诺跨页快照。
func (c *Client) ListTasks(ctx context.Context, in ListTasksRequest) (TaskPage, error) {
	var out TaskPage
	if !validID(in.QueueID) || in.Limit < 0 || in.Limit > 100 || len(in.Cursor) > 1024 {
		return out, errors.New("invalid task query queue or page")
	}
	switch in.State {
	case "", TaskWaiting, TaskLeased, TaskRunning, TaskNeedsReview, TaskSucceeded, TaskFailed, TaskCancelled:
	default:
		return out, errors.New("invalid task state")
	}
	if !utf8.ValidString(in.BusinessKey) || utf8.RuneCountInString(in.BusinessKey) > 191 || strings.ContainsAny(in.BusinessKey, "\x00\r\n") {
		return out, errors.New("invalid business key filter")
	}
	q := url.Values{}
	q.Set("queue_id", in.QueueID)
	if in.State != "" {
		q.Set("state", string(in.State))
	}
	if in.BusinessKey != "" {
		q.Set("business_key", in.BusinessKey)
	}
	if in.Limit != 0 {
		q.Set("limit", strconv.Itoa(in.Limit))
	}
	if in.Cursor != "" {
		q.Set("cursor", in.Cursor)
	}
	for name, field := range map[string]*time.Time{"created_from": in.CreatedFrom, "created_before": in.CreatedBefore} {
		if field == nil {
			continue
		}
		v := field.UTC()
		if v.Year() < 2000 || v.Year() > 9998 || v.Nanosecond()%1000 != 0 {
			return out, errors.New("invalid task creation bound")
		}
		q.Set(name, v.Format(time.RFC3339Nano))
	}
	if in.CreatedFrom != nil && in.CreatedBefore != nil && !in.CreatedFrom.Before(*in.CreatedBefore) {
		return out, errors.New("created_from must be before created_before")
	}
	err := c.call(ctx, "GET", "/v1/tasks?"+q.Encode(), "", nil, &out)
	return out, err
}